Rich data (such as moving image data) and backup data, which have a large size and are hardly changed once created, are exemplified as data treated by storage apparatuses.
Further, a storage apparatus may be shared by a plurality of hosts, and parallel processing may be performed by a plurality of virtual machines (VMs) in a host. A back-end bandwidth, which is an interface bandwidth between a controller and a drive in the storage apparatus, is consumed in the case where the storage apparatus receives, in a high load state, a request from another host that shares the back-end bandwidth.
If the storage apparatus returns data stored in a cache memory in response to a Read request, such consumption of the back-end bandwidth can be reduced. The storage apparatus reads data ahead for sequential access, but the entirety of large-volume data cannot be stored in the cache memory. Further, concentrated sequential access to the same large-volume file by a large number of users causes an operation similar to random access to the same large-volume file. Accordingly, reload and purge are repeated in the cache memory, and a large amount of back-end bandwidth is consumed. Further, in hybrid cloud environments, the back-end bandwidth is consumed by contents access and internal processing, so that the responsiveness is likely to become lower.
A known technique involves replicating contents to another drive and allowing access to both the original contents and the replicated contents, to thereby improve the responsiveness (for example, PTL 1).